I'm still in the office at 7:25 p.m., but I'm feeling pumped. If I leave right now, I can get down to my local sushi joint and buy up the remaining salmon sashimi for less than half the price it costs at lunchtime before all the other local bargain hunters get to it.

My sushi joint is just one of many stores and cafes across London that would rather sell off its excess stock for the day for pennies than throw it in the bin. But even then, there's no guarantee it'll have leftovers at closing time. There's also no guarantee for me, the hungry customer, that it will have any of those duck rolls remaining that I like so much.

Enter - Karma - Dining - App - London

Enter Karma, a dining app that launched in London on Thursday. It matches up restaurants with food they need to get rid of and canny consumers like me who will jump at the chance to bag themselves a cheap meal. Restaurants list surplus food on the app for the less than half its original price. Consumers then purchase it from within the app and drop in to pick it up.

For customers, Karma eliminates the issue of speculatively popping your head around the door in the hope there's something on offer that day. This also opens the door to all kinds of establishments selling their otherwise unsold food. But apps like Karma do more than help sate the hunger of thrifty office workers and save restaurants money -- they are helping save the planet by eliminating food waste too.

Apps - Users - Practises - Lives

Apps can help users integrate practises into their daily lives.

While hunger remains one of the biggest challenges the world faces, we are also wrestling with the problem of excess food. Figures from the UN's Food and Agriculture Organization estimate that one third of all...